How do I maintain Echium wildpretii. How often do I water it and what type of sunlight does it nee to be in?
Here is an excellent article about this stunning specimen.
https://www.gardeningknowhow.com/ornamental/flowers/tower-of-jewels/echium-tower-of-jewels-info.htm
Hoping end result will produce blooms yearly via two consecutive years of planting, since TOJ is a biannual bloomer. Is that feasible, or would they all sync to the SAME rhythm?
No, these plants are Biennial. That means that they have a lifecycle of two years, total. The first year is spent growing vegetatively, and the second is spent reproducing. The seeds will start over the following year.
You can get some succession flowering by planting two separate years. When the first seed set is on its second year, plant a new set of seeds. They will grow, vegetatively, while the others are flowering. Once the flowering second year growth dies off, it will self seed, starting the cycle over. This will be a way to ensure that you get flowers every year.
Here is an article to help you with their care:
https://www.gardeningknowhow.com/ornamental/flowers/tower-of-jewels/echium-tower-of-jewels-info.htm